Computer simulation of the thermal fire resistance of building materials and structural elements

摘要

Prediction of the thermal fire resistance of building materials using a microcomputer based finite element analysis program is further reported in this paper. The thermal behaviour of three samples of commonly used materials including aluminium, hardwood and cement mortar were studied with one side exposed to an electric furnace. A small electric furnace was built with the transient variation of the furnace air temperature following the standard fire curve of British Standard BS476. Thermocouples were put inside the materials for monitoring the increase in temperature. Computer simulations with the finite element package was performed to study the temperature change inside the materials when they were exposed to fire. Results were compared with the experimental measurement on the transient temperature. Sensitivity analysis on the effect of element size was performed to check the results. Good agreement was found in the case of aluminium, but not so good in the cases of the other two building materials where other changes occurred at the same time - moisture evaporation from the cement mortar, and burning of the material of hardwood. Lastly, demonstrations in using the technique to study the thermal fire resistance of steel sheet, wooden doors and concrete beams were reported.